Heat Wave Warning
Overview
A heat wave warning is one of the meteorological special advisories issued by the Korea Meteorological Administration. It is activated when the daily maximum apparent temperature is expected to reach 35°C or higher for two or more consecutive days. Beyond a simple weather forecast, it serves as an official warning system to protect public health and safety. Upon issuance, local governments and relevant agencies enter an emergency response mode. Heat waves can cause heat-related illnesses such as heatstroke, heat exhaustion, and heat cramps, and are particularly fatal to the elderly, those with chronic diseases, and outdoor workers, making the warning system increasingly important. Due to the recent increase in the frequency and intensity of heat waves caused by climate change, the heat wave warning has become a core element of social disaster management, rather than mere weather information.
Main Content
Criteria and Issuance Procedure of Heat Wave Warning
The heat wave warning is determined according to the Korea Meteorological Administration's 'Heat Wave Special Advisory Issuance Criteria.' The current criteria in South Korea are as follows:
- Heat Wave Advisory: When the daily maximum apparent temperature is expected to be 33°C or higher for two or more consecutive days.
- Heat Wave Warning: When the daily maximum apparent temperature is expected to be 35°C or higher for two or more consecutive days.
The apparent temperature is an index that comprehensively considers temperature and humidity, reflecting the heat actually felt by people. The issuance procedure involves the Korea Meteorological Administration analyzing numerical weather prediction models and observational data to predict risk areas, then consulting with the relevant local government before announcing. Immediately upon issuance, it is disseminated nationwide via emergency broadcast messages (CBS), television, radio, and the internet.
History and Changes of Heat Wave Warning
In South Korea, heat wave special advisories were first implemented on June 1, 2008. Initially, they operated with a heat wave advisory (daily maximum temperature of 35°C or higher for one day) and a heat wave warning (daily maximum temperature of 38°C or higher for one day). However, the criteria were strengthened in 2011, changing to the current apparent temperature standard. In 2018, the worst heat wave on record occurred, leading to a sharp increase in the number of days heat wave warnings were issued. Subsequently, in 2022, the criteria for sending 'heat wave emergency text messages' were refined. In 2024, as part of climate change response, mandatory response measures by local governments (operation of cooling shelters, protection of vulnerable groups, etc.) upon issuance of a heat wave warning were legislated.
Social Impact of Heat Wave Warning
When a heat wave warning is issued, various impacts appear across society. First, in the health sector, the number of patients with heat-related illnesses surges. According to the Korea Disease Control and Prevention Agency's 'Heat-Related Illness Emergency Room Surveillance System,' emergency room visits increase by 3 to 5 times on days when a heat wave warning is issued compared to normal days. Particularly, the elderly aged 65 and over, those living alone, and outdoor workers (construction, agriculture, delivery, etc.) are the main vulnerable groups. Second, in the energy sector, a surge in cooling demand causes electricity peaks. In the summer of 2024, during the heat wave warning period, the maximum electricity demand exceeded 100 GW, raising concerns about blackouts. Third, in the economic sector, damage to agriculture and livestock farming is prominent. Annual losses of hundreds of billions of won occur due to livestock deaths, crop sunscald damage, and rising water temperatures in fisheries. Fourth, in transportation and infrastructure, issues such as melting of road asphalt, deformation of railway tracks, and restrictions on aircraft takeoffs and landings occur.
Response System and Action Guidelines
Action guidelines for the public when a heat wave warning is issued are as follows:
- Indoor Activities: Refrain from going out between 12:00 PM and 5:00 PM, and use air conditioners or fans to maintain indoor temperatures at 26–28°C.
- Hydration: Drink water regularly even if not thirsty, and avoid caffeinated or alcoholic beverages.
- Protection of Vulnerable Groups: Pay special attention to the elderly, those with chronic diseases, and children; checking on neighbors is important.
- Outdoor Work: Adjust work hours at construction sites and farms, and take breaks in the shade.
Local governments extend the operation of cooling shelters (senior centers, community centers, libraries, etc.) and implement measures such as cooling cost support for vulnerable groups and cool roof (roof heat blocking) projects.
Latest Trends
As of 2024–2025, the heat wave warning system is undergoing the following changes:
- Strengthened Criteria: In 2024, the Korea Meteorological Administration further refined the apparent temperature criteria and began additionally considering 'nighttime tropical nights' when issuing heat wave warnings. This is because the perceived risk increases when tropical nights (nighttime minimum temperature of 25°C or higher) persist.
- Introduction of AI Prediction: Starting in 2025, the Korea Meteorological Administration introduced an AI-based heat wave prediction model, increasing accuracy for up to three days ahead to over 90%. This model comprehensively analyzes temperature, humidity, wind speed, and urban heat island effects.
- Smart Response: Local governments have introduced 'smart shelters' utilizing IoT sensors, establishing real-time temperature and humidity monitoring and emergency contact systems. Additionally, personalized heat wave notification services via mobile apps are expanding.
- Linkage with Climate Change: The IPCC report published in 2025 projects that the number of heat wave days on the Korean Peninsula will triple compared to 1990, raising the need for a long-term reorganization of the heat wave warning system. Accordingly, the government is fully revising the 'Standard Manual for Heat Wave Disaster Crisis Management.'
- International Cooperation: Since 2024, South Korea, China, and Japan have established a joint East Asian heat wave response system, standardizing the criteria for issuing heat wave warnings and information sharing.
Related Topics
- [[Heat-Related Illness]]
- [[Climate Change]]
- [[Emergency Broadcast Message]]
- [[Cooling Shelter]]
- [[Tropical Night]]
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